The invention relates to a hinge for spectacles with a joint body used as a hinge axle, which body forms a coaxial circumferential groove for receiving an eye of a side jaw and is rotationally rigidly held between two legs of an end of a side, which legs are mutually connected at least at one end and extend on either side of the circumferential groove.
In known hinges of this type (WO 99/14628 A1), the two legs of the U-shaped bent end of the side penetrate the preferably spherical joint body on either side of the circumferential groove, with the connecting bridge between the two legs of the end of the side externally overlapping the wire eye of the side jaw, which wire eye is guided in the circumferential groove of the joint body and is open on the circumferential side. As a result of these measures, the joint body is held in a rotationally rigid manner between the legs of the U-shaped bent end of the side whose connecting bridge which overlaps the wire eye externally additionally makes any inadvertent unlatching of the wire eye from the circumferential groove of the joint body more difficult. The precondition for such a design is, however, that the wire eye of the side jaw is provided with sufficient flexural elasticity in order to allow the same to resiliently latch into the circumferential groove of the joint body by widening. If such elasticity properties cannot be ensured, which is the case for example in wire eyes made of a gold alloy or eyes which are closed off on the circumferential side, this otherwise advantageous design cannot be used.
Similar disadvantages are obtained in another known design (GB 2 281 979 A) in which the joint body of the hinge which is encompassed by the wire eye is not spherical but is configured in the form of a disk which can be associated with the side or the jaw of the side. The wire eye which is formed by the jaw or the side must again be widened accordingly in order to allow latching into the circumferential groove of the disk-like joint body, which again requires a sufficient flexural elasticity of the wire eye.
The invention is thus based on the object of configuring a hinge for spectacles of the kind mentioned above in such a way that wire eyes which are open on the circumferential side with a limited flexural elasticity or eyes which are closed off on the circumferential side can be used without having to take into account any complex mounting conditions.
This object is achieved by the invention in such a way that the joint body consists of two preferably disk-like parts whose abutting surfaces extend transversally to the hinge axis in the zone of the circumferential groove.
By dividing the joint body into two parts along a dividing surface extending transversally to the hinge axis in the zone of the circumferential groove, it is no longer necessary to accordingly widen the eye of the side jaw, because the two parts of the joint body can be inserted from opposite sides into the eye of the side jaw in the direction of the hinge axis. The eye can therefore be provided with an open and also closed arrangement on the circumferential side. In order to mount the joint body with the eye of the side jaw held between its parts, the joint body merely needs to be inserted between the two legs and its parts be connected in a rotationally rigid manner with the legs of the end of the side. The rotationally rigid fixing of the joint body constitutes an advantageous precondition to determine the running of the hinge by the friction between the eye and the joint body.
For this purpose the parts of the joint body can be provided at their mutually averted face sides with parallel receiving grooves for the two legs of the end of the side. In order to enable the insertion of such a joint body between the legs of the end of the side, the legs can be widened within the scope of their own elasticity, so that the eye with the inserted joint body can be inserted transversally to the legs. In the case of legs which are mutually connected at only one end, it is potentially also possible to insert the joint body from the open side of the legs in their longitudinal direction. No separate tools are necessary in both cases for mounting.
Various measures can be taken so as to prevent any inadvertent displacement of the joint body along the legs. Caulking or gluing between the legs and the joint body would be a possibility for example. Particularly simple constructional conditions are obtained, however, when the joint body can be latched into a latching recess of at least one leg, so that the joint body merely needs to be displaced along the legs into the latching recess in order to be held resiliently in said latching recess against any further displacement. This solution not only offers the advantage of a toolless assembly, but also that of a simple detachability
Since for inserting the joint body between the legs it is necessary to align the two parts of the joint body with respect to one another in such a way that the receiving grooves extend parallel on their mutually averted face sides, measures are recommended which secure this alignment during the introduction of the two parts of the joint body into the eye of the side jaw from opposite sides. For this purpose the two parts of the joint body can mutually engage with graded abutting surfaces which allow the axial joining of the two parts only in the intended alignment of the receiving grooves.
Another possibility to join the parts of the joint body with the legs of the end of the side is obtained in such a way that the legs of the end of the side are jointly mutually connected to form a receiving eye in which the joint body is held by a pin penetrating the same and that the two parts of the joint body are supported with respect to the receiving eye in a rotationally rigid way by way of rotational stops which engage in the latching recesses of the receiving eye and project axially beyond the joint body. In order to mount the joint body with the wire eye held between its parts, the joint body is introduced into the receiving eye formed by the end of the side and held in said receiving eye by a pin which penetrates the joint body in the direction of the hinge axis and engages with its ends which project on either side from the hinge body into bores of the legs of the end of the side. Since the two parts of the joint body are supported in a rotationally rigid way with respect to the end of the side by way of rotational stops engaging in latching recesses of the receiving eye, the running hinge is again determined by the friction between the wire eye and the joint body.
In order to dismount the hinge the joint body must be detached from the receiving eye of the end of the side, which requires a removal of the pin penetrating the joint body. This can be achieved in a simple manner in such a way that the pin is provided with a threaded section. A threaded pin screwed into the end of the side requires a respective female thread in the end piece, which not only increases the production work, but also leads to difficulties in the case of breakage of the threaded bolt. For this reason the pin provided with a self-cutting thread can merely be screwed into the joint body, so that it is held in the end of the side in a freely rotating way with the pin ends projecting on either side beyond the joint body. This measure allows omitting the cutting of a female thread. As a result of the inherent elasticity of the plastic of the joint body it is possible to ensure a secure holding of the pin in the joint body beyond the threaded section. The unscrewing of the pin from the joint body is simple, so that advantageous constructional conditions can be brought about. They are based on the fact that the parts of the joint body can be supported in a rotationally rigid way in the end of the side by way of the rotational stops, so that no torques caused by the actuation of the hinge are exerted on the pins.